JP5642016B2 - Production plan creation system and production plan creation method - Google Patents

Description

  The present invention relates to a production plan creation system and a production plan creation method that can reduce a physical quantity related to generation of a usage of a production facility that fluctuates according to a production plan.

  Various production plan creation methods have been proposed for each purpose. Patent Document 1 relates to product production with a production plan that shows the entire process from the arrival of raw materials of a product to the shipment of the product for the purpose of maximizing profit and shortening the production time of the product while complying with the delivery date of the product. It is described that it is created from various information and each process content or each process order of the production plan is changed.

  Patent Document 2 proposes a method for creating an overall optimum production plan for irregular orders such as discrete orders, express orders and production delays in the manufacturing industry. By changing the margin, which is the extra time added to the production plan, in conjunction with the fluctuation of the production plan using an adjustment function, the production plan can be modified for various irregularities, and other production plans Describes how to create a production plan that minimizes the impact.

  Moreover, in patent document 3, it considers energy demand data, the operating cost of a utility plant, and equipment performance in facilities, such as a manufacturing plant, so that the supply capacity of a utility plant exceeds a demand and it becomes the minimum operating cost. Describes that the start and stop of the equipment is determined to reduce the cost of equipment such as a manufacturing plant.

JP 2006-309577 A JP 2004-127170 A JP 2009-282799 A

  According to Patent Document 3, the operating cost of utility equipment that supplies power and steam, which is a utility plant, is considered, but only the operating status of the supply equipment is changed without changing utility demand. This reduces the operating cost. Since the operating cost of utility equipment is related to utility demand, further examination is required to obtain the minimum operating cost.

  In any case, it is necessary to sufficiently reflect the energy required for generating utility such as electricity, hot water, cold water, and steam used by the production facility, and the cost of CO2, etc., over the existing technology. In this specification, physical quantities (energy, CO 2, etc.) required to achieve a certain thing are collectively referred to as cost.

  The present invention is an invention for solving the above-described problems, and provides a production plan creation system and a production plan creation method capable of reducing a physical quantity related to generation of a usage of a production facility that varies according to a production plan. For the purpose.

In order to achieve the above object, the production plan creation system according to the present invention sets the location where the process start time is to be obtained and sets the usage amount to be used for the production line Petri net model based on the production line information input by the user. and the production line Petri net model creation unit created by the user so as to be set, and the utilities equipment information setting unit that sets the utilities equipment information of auditors equipment model for supplying the utilities to the production line, utilities equipment Based on the objective function setting unit that sets the physical quantity desired to be minimized as an objective function, the Petri net model, the utility equipment information, and the objective function, the conditions to be satisfied in the production line and the conditions necessary for the operation of the utility equipment Using the mathematical programming method as a constraint, the calculation to minimize the physical quantity of the utility equipment within the delivery date of the product is made, and the process start in the production line based on the calculation Calculator for determining between (e.g., restriction setting-optimization calculation unit 105) and having a.

  ADVANTAGE OF THE INVENTION According to this invention, the physical quantity which concerns on the production | generation of the use utility of the production facility which fluctuates according to a production plan can be reduced.

It is an example of the block diagram of the production plan preparation system in Embodiment 1. It is an example of a production line. It is an example of the structure of the compressor which supplies air to a production line. It is an example of the power consumption characteristic at the time of controlling the number of four compressors. It is an example of the figure which shows the outline | summary of a Petri net. It is a flowchart explaining the process of a production plan preparation method. It is an example of the figure which shows the element of the Petri net used when a user produces the model of a production line in a production line Petri net model creation part. It is the example which modeled the production line shown in FIG. 2 using the element of the Petri net of FIG. It is an example of the table | surface which shows the value setting of a place and a transition. It is an example of the figure which shows the air demand amount at the time of producing in line. In Embodiment 1, it is an example of the figure which shows the effect of using a production planning system. It is an example of the structure of the utility equipment in Embodiment 2. FIG. It is an example of the power generation efficiency characteristic and waste heat rate characteristic of a cogeneration system. It is an example of the fuel consumption characteristic of a several once-through boiler. In Embodiment 2, it is an example of the figure which shows the effect of using a production planning system.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 is an example of a configuration diagram of a production plan creation system 101 according to the first embodiment. The production plan creation system 101 includes a production line Petri net model creation unit 102 that creates a Petri net model of the production line 110 based on the information of the production line 110 input by the user 106, and information on the utility equipment 109 input by the user 106. A utility facility information setting unit 103 for setting various types of information of the utility facility 109 based on the cost, an objective function setting unit 104 for setting a cost to be minimized such as cost and CO2 (greenhouse gas emission), and a production line petri Based on the Petri net model of the net model creation unit 102, the utility facility information of the utility facility information setting unit 103, and the objective function set by the objective function setting unit 104, each of the production lines 110 in the production line 110 is minimized. Constraint setting / optimum calculation unit 105 (calculation unit) that determines the operation plan of the utility equipment 109 including the process start time Configured to include a. The process start time determined by the constraint setting / optimal calculation unit 105 is transmitted to the field worker 107 and the production line control device 108.

  As described above, in this embodiment, the physical quantities (cost, energy, CO 2, etc.) required to achieve a certain thing are collectively referred to as cost. In addition, the utility facilities 109 include facilities that handle steam, electric power, compressed air, and the like necessary for the production line 110.

  FIG. 2 is an example of the production line 110. The lines shown in FIG. 2 are 7 in Step 1 (202), Step 2 (203), Step 3 (206), Step 4 (207), Step 5 (208), Step 6 (210), and Step 7 (211). It has two steps. Step 1 (202) and step 2 (203) are a series of lines, and an intermediate product A is made from a part A put in from the storage 201 and temporarily placed in the storage 204. Step 3 (206), step 4 (207) and step 5 (208) are also a series of lines, and an intermediate product B is made from a part B input from the storage 205 and temporarily placed in the storage 209. In addition, in order to clarify the name and code of the part in step 1 (202), the code is appropriately described in parentheses.

  The process 6 (210) and the process 7 (211) are also a continuous line, and the intermediate product A and the intermediate product B are combined into a product and stored in the product storage area 212. In each storage place, a plurality of parts and intermediate products are put together in one container, and the process is carried out using this as one unit. In FIG. 2, as an example, a state in which the component 214 is stored in the container 213 is shown in a balloon. Regarding use of utility, air is used as utility in step 1 (202), step 4 (207), step 5 (208), and step 7 (211). The production line 110 is not limited only to this shape.

FIG. 3 is an example of a configuration of a compressor that supplies air to the production line 110. Refer to the drawings as appropriate. Details of the service facility 109 are shown in FIG. In order to supply air to the production line 110, four compressors A (301), B (302), C (303), and D (304) are used. These are all the same discharged air amount (1 [m ³ / min]). It is assumed that the compressor D (304) performs inverter control for adjusting the discharge air amount and performs unit control with four units. Among these, it is assumed that the efficiency of the compressor C (303) is lower than that of the other compressors A (301) and B (302).

  FIG. 4 is an example of power consumption characteristics when four compressors are controlled. In the case of controlling the number of units, since the compressor D (304), which is an inverter machine, takes charge of the partial load, the relationship between the power consumption and the air consumption is as shown in FIG. In the figure, A, B, C, and D indicate areas where the compressors A (301), B (302), C (303), and D (304) supply air. Which of the compressors A and B is started first is designated in advance, and the compressor C (303) having low efficiency is used only when the amount of air used is large so as not to be used as much as possible. As in the case of the production line 110, these do not limit the configuration / characteristics of the utility equipment 109.

  FIG. 5 is an example of a diagram showing an outline of a Petri net. Petri nets were devised as a tool for modeling discrete event systems, and consist of four basic elements: places, tokens, arcs, and transitions. Represent. A transition fires when the number of tokens in each place connected by arc exceeds the set value, erases the same number of tokens at the connection source, and places a predetermined number of tokens at the place of the connection destination by arc. Make it appear. Tokens are also used to model production states, assuming that they represent the state of work or directly the product. For example, there are JP-A-8-36602 and JP-A-11-328259.

  FIG. 6 is a flowchart for explaining the process of the production plan creation method. The process of the production plan creation method by the production plan creation system 101 will be described with reference to FIG. 1 as appropriate. First, the production line Petri net model creation unit 102 creates a Petri net model of the production line based on the settings of the user 106, and the utility equipment information setting unit 103 sets information on the utility equipment model (step S601). . The objective function setting unit 104 sets an objective function to be optimized, and the constraint setting / optimal calculation unit 105 sets a constraint condition (step S602). Then, the constraint setting / optimal calculation unit 105 performs optimization calculation (step S603).

In step S604, the constraint setting / optimum calculation unit 105 determines whether or not there is a condition change from the user 106. If there is a condition change (step S604, Yes), (1) Petri net model and utility model If it is a change request, the process returns to step S601, and (2) if it is a request to change the objective function and constraint conditions, the process returns to step S602. On the other hand, if there is no condition change (step S604, No), the process ends.
Hereinafter, details of each flow will be described in the case of production equipment and utility equipment.

  FIG. 7 is an example of a diagram showing Petri net elements used by the production line Petri net model creation unit 102 for the user 106 to create a model of the production line 110. The creation of a Petri net model for the production line in step S601 will be described with reference to FIG. As places, there are a place 701 (see FIG. 7A) showing the production line 110 and a place 703 (see FIG. 7C) showing the outside of the production line 110. For example, when the user 106 (see FIG. 1) clicks the place 701 on the screen with a mouse or the like, a sub-screen shown in the table 701T is displayed. The user 106 consumes when the initial number of tokens and tokens exist. The type of role (utility type) and amount (utility amount) and the unit of utility (utility unit) are set. In the table 703T related to the place 703, an upper limit number and an initial number are set. The table 701T does not have an upper limit number column, but the upper limit number of the place 701 is 1 and is fixed. As the usage amount, a maximum usage amount or an average usage amount required for processing or work in the process is set. In Table 701T, when both electricity and steam (steam) are used as utility, electricity and steam can be set individually.

  As the transition, a transition 704 (see FIG. 7 (e)) that can specify the time from ignition to the extinction / generation of the token, and the transition 706 (FIG. 7 (g)) that is used for the position where the start time of the process is to be obtained. See). In the table 704T related to the transition 704 (see FIG. 7F), time and time unit can be set.

  As an arc, there is an arc 707 (see FIG. 7H) that connects between place transitions indicated by arrows.

  FIG. 8 is an example in which the production line shown in FIG. 2 is modeled using the elements of the Petri net in FIG. FIG. 9 is an example of a table showing place and transition value settings. Details of the flow 201 to 204 shown in FIG. 2 will be described. FIG. 8 will be described assuming that the user 106 uses the model creation screen displayed by the production line Petri net model creation unit 102 to create. The production line Petri net model creation unit 102 checks the consistency of the input production line Petri net model, and if there is an input error or the like, it may notify the display screen to that effect.

  First, a place for the part A is represented by a place 801. Here, assuming that there is a container containing five parts A at the beginning, a value of the initial number 5 is set as shown in a table 901 shown in FIG. Subsequently, in order to determine when it is desired to start the process 1 (202), a transition 802 for determining the start time is provided immediately before the line. A subsequent place 803 represents step 1 (202). Here, since air is consumed, values are set as shown in a table 902 shown in FIG.

  In the subsequent transition 804, the time required for the step 1 (202) is set as shown in a table 903 shown in FIG. 9C. The subsequent place 805 is step 2 (203), and no utility is used here, so no utility amount is set.

  In the same manner, the place of the intermediate product A, which is obtained by designating the time of the step 2 (203) in the transition 806 and subsequently completing the steps 1 (202) and 2 (203), is represented by a place 807. . The other steps 3 (206) to 7 (211) are similarly modeled as one step and one place. Since the process 6 (210) cannot be started unless the intermediate product A and the intermediate product B are prepared, the condition is reflected in the model by connecting the arc 808 and the arc 809 to the transition 810. Finally, the completed product is accumulated in a place 816 that is a storage place.

In this embodiment, in addition, the initial number is 5 for the place 817, air is 1 [m ³ / min] for the place 818, air is 1.0 [m ³ / min] for the place 819, and air is 1 [m for the place 820. ³ / min], and the time for each process is 10 [min], and 10 [min] is set for all transitions 704 (see FIGS. 7E and 7F).

FIG. 10 is an example of a diagram illustrating the air demand when production is performed according to circumstances. The eventual production is a case where control of production start time of the process is not performed at all. That is, this corresponds to placing the transition 704 of time 0 (see FIG. 7E) at that position without using the transitions 802, 810, and 821. Referring to FIG. 10, the air demand exceeds 3 [m ³ / min] between 40 [min] and 50 [min], and compressor C (303), which is less efficient than FIG. 4, is used. I understand that

  In the model shown in FIG. 8, the process is set as one unit. However, it is naturally possible to assemble the model such that the process is further divided or a plurality of processes are combined into one. It can be set arbitrarily. Further, it is not necessary to set the process start time at all immediately before the continuous line, and it may be provided in the middle of the line if it can be stopped on the line. In addition, when there is a distance from the place 807 as the storage place to the process 6 from the place 815 as the storage place and it is desired to set the minimum time until the start of the process, a timed transition and place (not shown) are placed before the arc 808 and the arc 809. This can be dealt with by providing a token and temporarily placing a token there. The production line Petri net model creation unit 102 (see FIG. 1) digitizes the Petri net model created by the user 106 (see FIG. 1) for optimization calculation.

A Petri net that can specify the time from firing to annihilation / generation of tokens in a transition is called a time Petri net, and the transition of the number of tokens in a place is expressed by the following formula. Reference is made to FIG. 7 as appropriate.

  The right-hand side of the first expression (formula 1) of Formula 1 is composed of the first term to the third term, where the first term is the number of markings at time k (the number of tokens) in a place and the second term is This is a term that represents the amount of token movement from the transition 704 to the corresponding place on the basis of the transition. Σ in the second term is used to check whether or not the number of tokens is more than the specified number before a certain transition. If it is, 1 is set, and 0 is set otherwise. (See Equation 2). W (t, p) -w (p, t) in the second term indicates the number of token movements, and for e, Equation 3 is referred to. The third term is a term representing movement of the token from the transition 706 to the corresponding place. In the third term, w (tc, p) -w (p, tc) indicates the number of token movements, and B is represented by 0 or 1 indicating the firing of transition tc (whether or not tokens can be generated or deleted). It is a variable, and by obtaining the solution using this value as an optimization variable, it is possible to determine the process start time at which the cost of the utility equipment is minimized.

Note that m is a marking and indicates the number of tokens in a place, and m ⁺ is used to represent a transition before time advances by 1. w is a component of the connection matrix indicating the connection between the place and the transition and its weight. The fact that “+” is attached to the right shoulder in m ⁺ (p, k) indicates the time when the time k advances to k + 1. k is time, and the state transitions as it progresses. p represents a place (place 701, place 703), t represents a transition 704, and tc represents a number of the transition 706 (a number that is appended with 2, 3, 4,.

e, σ, and σc represent conditions such as allowing the token to disappear / generate when the remaining time of the token time transition becomes 0, and are given by the following formulas 2, 3, and 4. . Of these, θ is a time set in the transition 704 using the table 704T, and c, c ⁺ , and σ ⁺ are values determined by other values as time advances.

C (t, k) in equation (3) is a time count after the arrival of the token at transition 704, and is a value that decreases every unit time after being set in equation (4). When the count reaches 0, e becomes 1, and the token can be moved according to Equation 1 together with 1 of σ. The subscript “+” in Equation 4 indicates a stage during which time k advances by 1 (k → k ⁺ → k + 1). This is necessary for calculation, and the meaning of the variable itself is the same for both c and c ⁺ . c ⁺ resets the time when the token arrives before the transition and it becomes possible to pass through. Otherwise, it decreases by one.

  The production line Petri net model creation unit 102 obtains w from the Petri net model created by the user from the initial number of markings at time 0 required for this expression, the time θ set for the transition, and the connection between the place and the transition. . The number of place and transition may be arbitrary, so it may have a function of automatically assigning numerical data from the model after generating the model, or the user assigns a number one by one when generating the model. You may do it. However, it should not be duplicated.

  When the marking m (p, k) and the usage amount (u (p)) set in Table 701T are used, the usage amount U (k) is expressed by the following equation. Generated internally and used for optimal calculations.

  Subsequently, the utility facility information setting unit 103 will be described in order to describe the utility facility model information input in step S601 of FIG. Here, the user 106 uses the utility amount and load factor for each utility facility (the output at the time of partial load of the utility facility / rated output of the utility facility; ), And the relational expression between energy and load factor. In the case of the unit operation of the same discharge air amount compressor of the present embodiment, since the relationship between the usage amount (air) usage amount and the energy consumption amount (electric power consumption amount) is uniquely determined from FIG. Calculate as equipment 109.

  If the equipment load factor (air discharge amount / air rated output for 4 units) is x (k) (k is time) and the rated air discharge amount for 4 units is α, the air usage Ua (k) = Α × x (k). The relationship with the power consumption E (k) is created and input by the user using FIG. If it is the general method which divides | segments into a several area and sets up a linear approximation formula for each, it will become the form of the following Numerical formula 6.

  i represents each section, and z is a variable of 1 or 0. It functions so that one section is selected under the condition that the sum is 1 or less. The user 106 sets a (i) and b (i) corresponding to α and the number of section divisions. As described above, the utility facility model information is set in step S601 (see FIG. 6) by the utility facility information setting unit 103.

  Next, the setting of the objective function in step S602 in FIG. 6 will be described. The cost of the utility equipment may be energy, CO2, etc. In this case, the power consumption E (k) is added with respect to time. The user 106 inputs the addition time (a value that is equal to or greater than the limit time for the end of product manufacture). In the formula, the following formula 7 is obtained.

Equation 7 shows an objective function that is a physical quantity to be minimized by the utility equipment 109.

  Next, the setting of constraint conditions in step S602 in FIG. 6 will be described. In performing the optimization calculation, it is necessary to use an objective function and constraint conditions. The objective function is set as the total energy consumption by the objective function setting unit 104, and the energy consumption of the utility equipment 109 is added.

  As a constraint equation for the constraint condition, the following constraint equation is used from the condition that the utility amount is equal between the Petri net model of the production facility and the model of the utility facility 109. This formula is established for each utility type.

  The optimization of the utility model and the production line Petri net model is linked by Equation 8. The necessary values are set by the constraint setting / optimal calculation unit 105 from the production line Petri net model creation unit 102 and the utility equipment information setting unit 103.

  In addition to minimizing energy consumption, it is necessary to meet the delivery date, so the time you want to finish production is k_M, and the number of products you want to make (counted as one per container) is m_s, Assuming that the place number representing the product place is p_f (final place), k_M and m_s are input by the user, and p_f is automatically acquired for the place at the end in the production line Petri net model. In this embodiment, the number of products to be created is five containers, and the product creation end is within 100 [min], and each value is input to k_M and m_s.

  In addition, the upper limit of the number of markings is also acquired from the production line Petri net model creation unit 102 to create a constraint equation. In addition, when it is desired not to exceed a certain number over a plurality from the production line to the storage place, the equation is set here. In addition, as for other restrictions, the mathematical formulas from the previous formula 1 to the formula 4 are entered.

  After the creation of the constraint equation, the constraint setting / optimal calculation unit 105 performs optimization calculation in step S603 of FIG. This optimization calculation problem is solved as a constraint satisfaction problem because it includes nonlinear terms due to conditional branches. In order to obtain an energy saving effect, it is not always necessary to obtain an optimal solution, and it may be solved by an exact solution based on the backtracking method, or an approximate solution using a local search or a tabu search. As a solution, the production process start time B (tc, k) and the load factor of the utility equipment are determined.

  Specifically, B (tc, k) is a variable that permits the token to pass through the transition 706 (1: permitted, 0: not permitted). When this is 1, the token is allowed to pass. In other words, advancing a product to the line means starting a production process.

  In the first embodiment, the production process start time is always 1 for the transitions 802 and 821, 0 for the transition 810 between 40 [min] and 50 [min], and 1 otherwise. Is obtained. As can be seen from the equation (1), this period indicates that tokens cannot be erased / generated in places before and after this transition 810, which means that the start of step 6 (place 811) is delayed by 10 minutes.

FIG. 11 is an example of a diagram illustrating an effect of using the production planning system in the first embodiment. A line 1102 indicated by a broken line is an air demand corresponding to the example of FIG. 10, and a line 1101 indicated by a solid line is an air demand after the optimization calculation. As described above, the air demand amount is as indicated by the line 1101, unlike the case of the line 1102 corresponding to the example of FIG. 10. The load factor of utility equipment obtained as a solution corresponds to (value of solid line 1101) / (sum of air rated discharge air amount of all compressors). Compared with the air demand corresponding to the example of FIG. 10 (dashed line 1102), the air demand falls below 3 [m ³ / min], so that the air is not used without using the inefficient compressor C (303). It turns out that it can supply. In addition, the condition that product production is completed within 100 minutes is also satisfied.

  In this way, by optimizing the process start time, it becomes possible to use only the energy efficient one of the compressors, and it is possible to reduce energy.

(Embodiment 2)
In the second embodiment, it will be described that when the operation state of the utility equipment can be controlled, the operation plan can also be made. A description will be given with reference to FIG. The overall configuration of the production plan creation system 101 is the same as that shown in FIG. The process flow for producing the production plan is the same as that shown in FIG.

  FIG. 12 is an example of the configuration of utility equipment in the second embodiment. The utility equipment 109 in FIG. 1 includes a cogeneration system 1201 (CGS), a waste heat boiler 1203, and a once-through boiler 1202, as shown in FIG. The production line 110 uses electricity generated by the power purchase 1205 and electricity generated by the cogeneration system 1201. Assuming that the cogeneration system 1201 performs an electric main heat slave operation, the waste heat at the time of power generation is changed to steam by the waste heat boiler 1203 and used for the air conditioning 1204. It is also assumed that the amount of electricity generated can be specified (operation control is possible). When the heat of the waste heat boiler 1203 is insufficient for the air conditioning demand, steam is replenished with the once-through boiler 1202.

  The production line 110 is a line represented in FIG. 2 as in the first embodiment. However, in Step 1 (202), Step 4 (207), Step 5 (208) and Step 7 (211), it is assumed that electricity is used not for air but for electric heating. Therefore, in the designation of the utility type at the time of creating the production line Petri net model in step S601 in FIG. 6, electricity is selected as the utility type in the table 701T in FIG. 7, and the necessary amount and unit are input. Line modeling using a Petri net is performed in the same manner as in FIG. In this example, the electric power for operating the production line is excluded, but if the value is so large that it cannot be ignored, it is only necessary to add the total electric energy to be accepted.

For each utility facility, details necessary for specifying the utility facility model information in step S601 of FIG. 6 will be described below. FIG. 13 is an example of power generation efficiency characteristics and exhaust heat ratio characteristics of the cogeneration system 1201. FIG. 13 shows a graph 1301 of the power generation efficiency and a graph 1302 of the exhaust heat ratio when the ratio of the output with respect to the rated output of the gas engine is used as the load factor for the cogeneration system 1201. As shown in the graph 1301, the higher the load factor, the higher the power generation efficiency. Conversely, as shown in the graph 1302, the exhaust heat rate tends to be saturated and becomes smaller. Let x be the load factor.
Graph 1301 is set as ae (i) × x + be (i),
The graph 1302 is set to ah (i) × x + bh (i).
Note that i represents a section.

And let the fuel consumption with respect to a load factor be af (i) * x + bf (i).

Next, regarding the power purchase 1205, it is assumed that the unit price cbuy changes as follows according to the usage amount ebuy by the contract with the electric power company.
cbuy = c1 (0 <ebuy <e1), c2 (e1> ebuy)

FIG. 14 is an example of fuel consumption characteristics of a plurality of once-through boilers. FIG. 14 is a graph 1401 showing the relationship between the steam consumption and the fuel consumption when there are a plurality of once-through boilers 1202 because the efficiency is substantially constant. In this example, the steam generation amount of each once-through boiler is small with respect to the steam demand, and assuming that the number is large, a linear approximation of the steam consumption and the fuel consumption is performed as shown in a graph 1402. At this time, if the steam use ratio with the maximum amount of steam generated when all the once-through boilers 1202 are used is the load factor xboil, the fuel consumption is
fa × xboil + fb
It can be expressed. Even if approximation is not possible, it can be handled by formulating each individual device.

  Regarding the waste heat boiler 1203, it is assumed that the heat quantity of the proportion β can be given to the air conditioner 1204 in the exhaust heat of the cogeneration system 1201.

  In the air conditioner 1204, the heat demand is set to ha (l) [J]. l is time and the unit is “time”. It is assumed that the time k of the production line Petri net model is “minute” as in the first embodiment. This time can be specified when each item is set by the production line Petri net model creation unit 102 and the utility equipment information setting unit 103, respectively. This is because the Petri net model of the production line is usually a model of minute units, while the operation plan of the heat source facility such as a cogeneration system is made in units of one hour.

The objective function in step S602 in FIG. Equation 10 shows an objective function that is a physical quantity that the utility equipment 109 wants to minimize.

  Equation 10 is an expression of the objective function, and is composed of two terms, Σ (first term) for k and Σ (second term) for l. The first term is the cost of electricity used for electricity purchase. The second term is a fuel cost obtained by multiplying a fuel consumption amount obtained by adding a fuel consumption amount of the cogeneration system 1201 and a fuel consumption amount of the once-through boiler 1202 by a conversion factor fc into a cost. That is, the total cost (total cost) is obtained by adding the cost of electricity and the cost of fuel, and is used as an objective function. Expenses are a form of cost.

  Finally, the constraint condition in step S602 in FIG. 6 is set. Since it is necessary to satisfy the electric power required for the production line and the heat demand required for the air conditioning, two formulas (11) are created. The first formula (upper stage) represents the coincidence between the demand and supply for power, and the second formula (lower stage) represents the coincidence between the demand and supply for steam. The total amount of steam when the once-through boiler 1202 is rated for operation is set as w, and the amount of heat that can be added to the air conditioning per unit steam is set as qw.

  Describing Equation 11 in detail, U (k) on the left side of the first equation (upper stage) is the electric consumption of the production line 110, and obtains the maximum value within one hour. The value must be secured by the utility equipment 109. The right side of the first formula (upper stage) consists of two terms, the first term and the second term, where the first term is the amount of electricity obtained by electricity purchase, and the second term is the electricity generated by the cogeneration system (CGS). Amount.

The second formula (lower) h (k) is the amount of heat required for air conditioning every minute, and similarly, the maximum value within one hour is obtained on the left side. The right side of the second equation (bottom) consists of two terms, the first term and the second term. The first term is converted to heat by multiplying the steam consumption of the once-through boiler by the coefficient q _w (l). doing. The second term is the amount of exhaust heat output when the CGS is operated at the load factor x, and is converted into the amount of exhaust heat used for air conditioning by multiplying the coefficient β.

  The calculation of the maximum value of both equations is performed in order to match the time of both models. At this time, since it is necessary to make the operation plan so that the maximum value of the demand amount obtained by the Petri net model can be output by the operation plan of the cogeneration system, this is the form. The constraint setting / optimal calculation unit 105 compares the time of both models and adjusts the time to the larger side.

  The other constraints (Equation 9) indicating product manufacturing within the time limit, and other constraint formulas for the production line Petri net model and utility equipment model are the same as in the first embodiment. The optimization calculation in step S603 in FIG. 6 is the same as that in the first embodiment.

  As a solution, as in the first embodiment, the production process start time and the load factor of the utility equipment are determined. This makes it possible to simultaneously optimize both the operation plan optimization of the utility facility cogeneration system 1201 and the process start time of the production line 110.

  FIG. 15 is an example of a diagram illustrating an effect of using the production planning system in the second embodiment. In normal utility equipment optimal operation in which optimization is performed between the cogeneration system 1201 and the purchased power 1205 and the once-through boiler 1202, even if the cogeneration system 1201 is fully operated, the purchased power 1205 is contracted as shown in the graph 1501. If the power consumption threshold e1 (1503) is slightly exceeded, an increase in cost may not be avoided. By combining this with optimization of the production process start time, the cost can be reduced without exceeding the power consumption threshold e1 (1503) of the contract power as shown in the graph 1502.

  When minimizing the cost, when there are a plurality of physical quantities to be evaluated, there are two or more physical quantities that have a trade-off with each other. In this case, it is preferable to set an appropriate weight value (change the size depending on which one you want to evaluate more) to the two physical quantities and minimize the sum. In the case where there is one physical quantity, if the weight value of the other cost is 0 and the weight value of the cost to be evaluated is 1, the evaluation is for one physical quantity.

  For example, as physical quantities, there are expenses as operating expenses of the utility equipment 109 and greenhouse gas emissions of the utility equipment 109, and a weighted sum is designated. More specifically, when considering the cost of the utility facility 109 and the greenhouse gas (for example, CO2) emission amount of the utility facility 109, the cost may be low but the CO2 emission amount may increase. If the weight values are α and β, then α × (operating cost / M ¥) + β × (CO2 emission / t), and if you want to reduce the cost, “α × (cost / ¥)” A weight value is set so as to be larger with respect to “β × (CO2 emission / t)”. Since costs and greenhouse gas emissions are different in the first place, it is better that the user sets appropriate values depending on how much importance is given to α and β.

  To summarize the above, according to the first embodiment, the Petri net model includes a transition (for example, transitions 802, 810, and 821 shown in FIG. 8) indicating a place where the process start time is to be obtained. Amount can be specified. For example, the process 1 (202) of the place 803 is designated in the table 902 shown in FIG.

  According to the first embodiment, the utility facility information setting unit 103 sets energy consumption characteristics with respect to the load factor of the utility facility, and the objective function setting unit 104 is necessary for the operation of the utility facility as a physical quantity cost. The energy consumption is set, and the constraint setting / optimal calculation unit 105 can calculate the load factor as a variable together with the product flow of the production line, and create a production plan that minimizes the energy consumption required for operation. .

  In addition, this invention is not limited to above-described embodiment, Various modifications are included. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 101 Production plan creation system 102 Production line Petri net model creation part 103 Utility equipment information setting part 104 Objective function setting part 105 Constraint setting / optimal calculation part (calculation part)
106 user 107 field worker 108 production line control device 109 utility equipment 110 production line 701, 703 place 704, 706 transition 701T, 703T, 704T table 707 arc 1201 cogeneration system 1202 once-through boiler 1203 waste heat boiler 1204 air conditioning 1205 power purchase

Claims (8)

A production line Petri net model that creates a Petri net model of a production line based on the production line information input by the user so that the user can set the usage amount while setting the location where the process start time is desired. The creation department;
A utility equipment information setting unit for setting utility equipment information of a utility equipment model that supplies utility to the production line;
An objective function setting unit that sets, as an objective function, a physical quantity to be minimized in the utility equipment;
Based on the Petri net model, the utility equipment information, and the objective function, using mathematical programming as a constraint on conditions to be satisfied in the production line and conditions necessary for operation of the utility equipment, A production plan creation system comprising: a calculation unit that performs a calculation for minimizing a physical quantity of the utility equipment within a delivery date of the product, and determines the process start time in the production line based on the calculation. Among the elements of the Petri net model created in the above claims wherein the portion to be determined the process start time is defined by the transition, the utilities usage, characterized in that its utilities usage place being specified The production plan creation system according to 1. The production plan creation system according to claim 1, wherein the physical quantity includes at least one of an operating cost of the utility facility and a greenhouse gas emission amount of the utility facility. The utility equipment information setting unit sets energy consumption characteristics with respect to a load factor of the utility equipment,
The objective function setting unit sets energy consumption necessary for the operation of the utility equipment as the physical quantity,
2. The calculation unit according to claim 1, wherein the calculation unit calculates the load factor as a variable together with a product flow of the production line and creates a production plan that minimizes energy consumption required for the operation. Production planning system. A production plan creation method for a production line having utility facilities for supplying utilities,
The production line Petri net model creation unit sets the location where the process start time is to be obtained for the production line Petri net model based on the production line information input by the user , and the user can set the usage amount. to create a certain manner,
The utility facility information setting unit sets utility facility information of a utility facility model that supplies utility to the production line,
The objective function setting unit sets, as an objective function, a physical quantity that is to be minimized in the utility equipment,
Based on the Petri net model, the utility equipment information, and the objective function, the calculation unit uses the mathematical programming method with the conditions to be satisfied in the production line and the conditions necessary for the operation of the utility equipment as constraints. A production plan creation method comprising: performing calculation for minimizing a physical quantity of the utility equipment within a delivery date of a product, and determining the process start time in the production line based on the calculation. The portion of the created Petri net model element where the process start time is to be obtained is determined by a transition, and the utility usage is specified in a place. 5. The production plan creation method according to 5. The production plan creation method according to claim 5, wherein the physical quantity includes at least one of an operating cost of the utility facility and a greenhouse gas emission amount of the utility facility. The utility equipment information setting unit sets energy consumption characteristics with respect to a load factor of the utility equipment,
The objective function setting unit sets energy consumption necessary for the operation of the utility equipment as the physical quantity,
The said calculation part calculates the said load factor as a variable with the flow of the product of the said production line, and produces the production plan which minimizes the energy consumption required for the said driving | operation. Production plan creation method.

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